18081409 has 2 divisors, whose sum is σ = 18081410. Its totient is φ = 18081408.

The previous prime is 18081389. The next prime is 18081431. The reversal of 18081409 is 90418081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15840400 + 2241009 = 3980^2 + 1497^2 .

It is a cyclic number.

It is not a de Polignac number, because 18081409 - 2⁵ = 18081377 is a prime.

It is not a weakly prime, because it can be changed into another prime (18081439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9040704 + 9040705.

It is an arithmetic number, because the mean of its divisors is an integer number (9040705).

Almost surely, 2^18081409 is an apocalyptic number.

It is an amenable number.

18081409 is a deficient number, since it is larger than the sum of its proper divisors (1).

18081409 is an equidigital number, since it uses as much as digits as its factorization.

18081409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 18081409 is about 4252.2240063289. The cubic root of 18081409 is about 262.4686414543.

The spelling of 18081409 in words is "eighteen million, eighty-one thousand, four hundred nine".